> ## Documentation Index
> Fetch the complete documentation index at: https://cofhe-docs.fhenix.zone/llms.txt
> Use this file to discover all available pages before exploring further.

# Common Errors

> Critical limitations and important considerations when working with CoFHE, including common issues and Solidity error references

## Overview

This page documents critical limitations and important considerations when working with CoFHE. Understanding these common issues and error messages will help you troubleshoot problems and build more robust FHE-enabled smart contracts.

<Warning>
  Always verify you're using compatible component versions. Many errors can be resolved by ensuring you're using the latest versions of all CoFHE components.
</Warning>

<Card title="Quick Error Decoding" icon="terminal" href="/fhe-library/reference/cofhe-errors">
  Encountering cryptic `execution reverted: 0x...` errors? Use the **@fhenixprotocol/cofhe-errors** package to decode them instantly:

  ```bash theme={null}
  npx cofhe-errors 0x118cdaa7
  ```

  See the [CoFHE Errors Package](/fhe-library/reference/cofhe-errors) documentation for full usage instructions and the [Error Reference](/fhe-library/reference/cofhe-errors-reference) for a complete list of all 53 errors.
</Card>

## Common Issues

### Missing Revert Data

If you encounter a `Missing revert data` error, verify that you're using the latest `cofhe-contracts` version.

<Steps>
  <Step title="Check your version">
    Verify the version of `cofhe-contracts` in your project:

    <CodeGroup>
      ```bash npm theme={null}
      npm list @fhenixprotocol/cofhe-contracts
      ```

      ```bash yarn theme={null}
      yarn list --pattern "@fhenixprotocol/cofhe-contracts"
      ```

      ```bash pnpm theme={null}
      pnpm list @fhenixprotocol/cofhe-contracts
      ```
    </CodeGroup>
  </Step>

  <Step title="Compare with compatibility guide">
    Check the [Compatibility](/get-started/introduction/compatibility) page to ensure you're using a supported version.
  </Step>

  <Step title="Update if necessary">
    If your version is outdated, update to the latest compatible version:

    <CodeGroup>
      ```bash npm theme={null}
      npm install @fhenixprotocol/cofhe-contracts@latest
      ```

      ```bash yarn theme={null}
      yarn add @fhenixprotocol/cofhe-contracts@latest
      ```

      ```bash pnpm theme={null}
      pnpm add @fhenixprotocol/cofhe-contracts@latest
      ```
    </CodeGroup>
  </Step>
</Steps>

<Note>
  This section will be expanded over time as new issues arise. If you encounter an issue not documented here, please report it to the Fhenix team.
</Note>

## Possible Errors from Solidity

The following table lists common Solidity errors you may encounter when working with CoFHE contracts. Each error includes a description to help you understand what went wrong and how to fix it.

| Error                              | Description                                                                                                                  |
| ---------------------------------- | ---------------------------------------------------------------------------------------------------------------------------- |
| **InvalidInputsAmount**            | Operation requires a specific number of inputs. Occurs when an operation receives the wrong number of arguments              |
| **InvalidOperationInputs**         | Operation inputs must be valid for the operation. Thrown when inputs violate operation requirements                          |
| **TooManyInputs**                  | Operations have maximum input limits. Error when input count exceeds the operation's maximum                                 |
| **InvalidBytesLength**             | Byte arrays must match expected length. Occurs when byte array length doesn't match the required size                        |
| **InvalidTypeOrSecurityZone**      | Operations must use compatible types and security zones. Occurs when an operation violates type or security zone constraints |
| **InvalidInputType**               | Input must match the expected type. Error when input type doesn't match function requirements                                |
| **InvalidInputForFunction**        | Function inputs must match defined parameters. Thrown when a function receives an incompatible input type                    |
| **InvalidSecurityZone**            | Operations must stay within defined security zones. Error when an operation violates security zone constraints               |
| **InvalidSignature**               | Cryptographic signatures must be valid. Occurs with signature verification failures                                          |
| **InvalidSigner**                  | Signer must match the expected authorized address. Error when transaction signer doesn't match the required address          |
| **InvalidAddress**                 | Address must be valid and non-zero. Error when an invalid address is provided                                                |
| **OnlyOwnerAllowed**               | Function restricted to contract owner. Error includes the address of the unauthorized caller                                 |
| **OnlyAggregatorAllowed**          | Function restricted to authorized aggregator. Error includes the address of the unauthorized caller                          |
| **AlreadyDelegated**               | Delegatee contract is already a delegatee for sender and delegator addresses. Error when attempting duplicate delegation     |
| **SenderCannotBeDelegateeAddress** | Sender cannot be the delegatee address. Error when sender tries to delegate to themselves                                    |
| **SenderNotAllowed**               | Sender address not authorized for allow operations. Error includes the address of the unauthorized sender                    |
| **DirectAllowForbidden**           | Direct handle allowance not permitted. Must use Task Manager. Error includes the address attempting direct allow             |

### Understanding Error Types

**Input Validation Errors:**

* `InvalidInputsAmount`, `InvalidOperationInputs`, `TooManyInputs`, `InvalidBytesLength`
* These errors indicate problems with how data is passed to FHE operations
* **Solution**: Verify that you're passing the correct number and type of arguments

**Type and Security Zone Errors:**

* `InvalidTypeOrSecurityZone`, `InvalidInputType`, `InvalidInputForFunction`, `InvalidSecurityZone`
* These errors occur when encrypted types don't match expected types or security zones
* **Solution**: Ensure encrypted values use compatible types (e.g., `euint32` matches `euint32`) and are in the correct security zone

**Authentication Errors:**

* `InvalidSignature`, `InvalidSigner`, `InvalidAddress`
* These errors relate to cryptographic verification and address validation
* **Solution**: Verify signatures are valid and addresses are properly formatted

**Authorization Errors:**

* `OnlyOwnerAllowed`, `OnlyAggregatorAllowed`, `SenderNotAllowed`, `DirectAllowForbidden`
* These errors indicate permission or access control violations
* **Solution**: Ensure the correct account is calling the function and that proper permissions are set

**Delegation Errors:**

* `AlreadyDelegated`, `SenderCannotBeDelegateeAddress`
* These errors occur when delegation operations are invalid
* **Solution**: Check that delegation hasn't already occurred and that sender and delegatee addresses are different

## Troubleshooting Tips

When encountering errors:

1. **Check error messages carefully**: The error name and description provide clues about what went wrong
2. **Verify input types**: Ensure encrypted values match expected types
3. **Check permissions**: Verify that `FHE.allowThis()` or `FHE.allowSender()` have been called where necessary
4. **Review component versions**: Ensure all CoFHE components are up to date
5. **Test in mock environment**: Use the mock environment to debug issues without network delays

<Tip>
  Many errors can be prevented by following [best practices](/fhe-library/introduction/best-practices) and ensuring proper access control management.
</Tip>

## Next Steps

* Use the [CoFHE Errors Package](/fhe-library/reference/cofhe-errors) to decode error selectors
* View the complete [Error Reference](/fhe-library/reference/cofhe-errors-reference) with all 53 errors
* Review the [Compatibility](/get-started/introduction/compatibility) page for version requirements
* Learn about [access control](/fhe-library/core-concepts/access-control) to prevent authorization errors
* Check [best practices](/fhe-library/introduction/best-practices) for secure FHE development